Stimulation Of Immune Response Research Articles

Proteomic Profiling of Plasma and Total Blood Exosomes in Breast Cancer: A Potential Role in Tumor Progression, Diagnosis, and Prognosis

Exosomes are directly involved in governing physiological and pathological conditions of an organism by transferring information (proteins, microRNA, etc.) from producing to receiving cells. We evaluated the influence of protein cargoes of exosomes from plasma, and exosomes from the total blood of healthy females (HFs) and breast cancer patients (BCPs), on crucial steps of tumor progression: EMT, cell proliferation, invasion, cell migration, stimulation of angiogenesis and immune response. We conducted a mass spectrometric analysis of proteomic content of exosomes isolated from samples using ultrafiltration and ultracentrifugation. Their nature has been verified using cryo-electron microscopy and flow cytometry. Bioinformatics analysis showed that 84% of common exosomal proteins were of cytoplasmic and vesicle origin. They perform functions of protein binding and signaling receptor binding, and facilitated the processes of the regulated exocytosis and vesicle-mediated transport. We observed that metabolism-related signaling pathways were enhanced in the exosome-mediated intracellular communication. Half of the identified exosomal proteins from blood of HFs and BCPs are involved in crucial steps of the tumor progression: EMT, cell proliferation, invasion, cell migration stimulation of angiogenesis, and immune response. Moreover, we revealed that proteomic profiles of exosomes from HF total blood were enriched with proteins inhibiting EMT, cell migration, and invasion. Tumor diagnostic/prognostic protein markers accounted for 47% of the total composition of cell-surface-associated exosomes (calculated as the difference between the total blood exosomes and plasma exosomes) from BCP blood. Breast cancer-associated proteins were equally represented in the blood cell-surface-associated exosomes and in the plasma exosomes from BCPs. However, hyper-expressed proteins predominate in the blood cell-surface-associated exosomes as compared to the plasma exosomes (64% vs. 14%). Using breast cancer proteins data from the Human Protein Atlas (HPA) (www.proteinatlas.org/), three favorable (SERPINA1, KRT6B, and SOCS3) and one unfavorable (IGF2R) prognostic protein markers were found in the BCP total blood exosomes. Further studies will be needed to determine whether identified new exosomal proteins from BCP blood are potential breast cancer diagnostic/prognostic markers or novel therapeutic targets.

Recombinant protein and synthetic THY domain peptide of Macrobrachium rosenbergii thymosin β4 exhibit protective effect against Aeromonas hydrophila infection

Thymosin β4 (Tβ4) is involved in cytokine secretion, nerve development, stimulation of wound healing, cancer progression, growth rate and immune response. The functions of Tβ4 in vertebrate have been widely studied, but the activities of each THY domain in invertebrate multirepeat β-thymosins remain unclear. In the present study, a new four THY domains Tβ4 gene was identified and characterized. The four THY domains have certain similarities in amino acid sequence, but MrThy4-D1 and MrThy4-D4 are predicted with α-helical structure, while MrThy4-D2 and MrThy4-D3 are random coils. The CD spectra results have confirmed the α-helical structure of synthetic MrThy4-D1 and MrThy4-D4 peptides. MrTβ4 was mostly expressed in hemocyte and hepatopancreas. The expression of MrTβ4 could be significantly up-regulated after Aeromonas hydrophila infections. The recombinant MrTβ4 protein was successfully produced and purified as the inclusion body. After refolding, both the recombinant MrTβ4 protein and the synthetic D1, D4 peptides exhibit certain antimicrobial activities to the selected Gram-negative and Gram-positive bacteria. The rMrTβ4 protein, synthetic MrThy4-D1 and MrThy4-D4 peptides all could increase the survival rate of M. rosenbergii against A. hydrophila infections, by improving the circulating hemocytes count, enhancing the antioxidant enzyme activities in hemolymph, or directly inhibition effect on bacteria. The present study not only enrich the understanding of the immune system of shrimp, but also lay an important foundation for the further development of MrTβ4 and antimicrobial peptide drugs.

Immune-Related Adverse Events Associated With Immune Checkpoint Inhibitor Therapy

As part of immune surveillance, killer T lymphocytes search for cancer cells and destroy them. Some cancer cells, however, develop escape mechanisms to evade detection and destruction. One of these mechanisms is the expression of cell surface proteins which allow the cancer cell to bind to proteins on T cells called checkpoints to switch off and effectively evade T-cell-mediated destruction. Immune checkpoint inhibitors (ICIs) are antibodies that block the binding of cancer cell proteins to T-cell checkpoints, preventing the T-cell response from being turned off by cancer cells and enabling killer T cells to attack. In other words, ICIs restore innate antitumor immunity, as opposed to traditional chemotherapies that directly kill cancer cells. Given their relatively excellent risk-benefit ratio when compared to other forms of cancer treatment modalities, ICIs are now becoming ubiquitous and have revolutionized the treatment of many types of cancer. Indeed, the prognosis of some patients is so much improved that the threshold for admission for intensive care should be adjusted accordingly. Nevertheless, by modulating immune checkpoint activity, ICIs can disrupt the intricate homeostasis between inhibition and stimulation of immune response, leading to decreased immune self-tolerance and, ultimately, autoimmune complications. These immune-related adverse events (IRAEs) may virtually affect all body systems. Multiple IRAEs are common and may range from mild to life-threatening. Management requires a multidisciplinary approach and consists mainly of immunosuppression, cessation or postponement of ICI treatment, and supportive therapy, which may require surgical intervention and/or intensive care. We herein review the current literature surrounding IRAEs of interest to anesthesiologists and intensivists. With proper care, fatality (0.3%-1.3%) is rare.

Abstract PO-046: Assessment of COVID-19 vaccine candidates: Prediction and validation of 174 SARS-CoV-2 epitopes

Abstract The recent outbreak of SARS-CoV-2 (2019-nCoV) virus has highlighted the need for fast and efficacious vaccine development. Stimulation of a proper immune response that leads to protection is highly dependent on presentation of epitopes to circulating T-cells via the HLA complex. SARS-CoV-2 is a large RNA virus and testing of all of its overlapping peptides in vitro to deconvolute an immune response is not feasible. Therefore, HLA-binding prediction tools are often used to narrow down the number of peptides to test. We tested 19 epitope-HLA-binding prediction tools, and using an in vitro peptide-MHC stability assay, we assessed 777 peptides that were predicted to be good binders across 11 MHC alleles. In this investigation of potential SARS-CoV-2 epitopes, we found that current prediction tools vary in performance when assessing binding stability, and they are highly dependent on the MHC allele in question. Designing a COVID-19 vaccine where only a few epitope targets are included is therefore a very challenging task. Here, we present 174 SARS-CoV-2 epitopes with high prediction binding scores, validated to bind stably to 11 HLA alleles. Our findings may contribute to the design of an efficacious vaccine against COVID-19. Citation Format: Marek Prachar, Sune Justesen, Daniel Bisgaard Steen-Jensen, Stephan Thorgrimsen, Erik Jurgons, Ole Winther, Frederik Otzen Bagger. Assessment of COVID-19 vaccine candidates: Prediction and validation of 174 SARS-CoV-2 epitopes [abstract]. In: Proceedings of the AACR Virtual Meeting: COVID-19 and Cancer; 2020 Jul 20-22. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(18_Suppl):Abstract nr PO-046.

Thermovaccination, thermoheliox as a stimulant of immune response. Kinetic model of process development.

A kinetic model is proposed to describe the key features of development of an acute viral infection, accumulation of antibodies, and immune response in the human body. The general features of immune system stimulation by thermoheliox are described. The model can be used for developing the basis for the application of thermoheliox in the treatment of patients affected by coronavirus.

Possible Mechanisms of Action of Two Pseudomonas fluorescens Isolates as Probiotics on Saprolegniosis Control in Rainbow Trout (Oncorhynchus mykiss Walbaum).

Simple SummaryIn aquaculture, as in other production systems, diseases caused by microorganisms can produce great economic losses and it is essential to have preventive or curative treatments for their control. However, there is increasing concern and restrictions on the use of chemical products for the treatment of such diseases. In this context the use of probiotics could be a good alternative to chemical treatment. Previous studies of our research group have shown the usefulness of two Pseudomonas fluorescens isolates for the biocontrol of saprolegniosis in rainbow trout—a disease caused by a pseudo-fungus that affects freshwater fish—under experimental conditions when they are added to the tank water. In the present work we investigated some of the possible mechanisms of action of these two isolates, such as stimulation of the immune response, competition for binding sites or sources of nutrients, and the production of bioactive substances inhibitory to pathogenic agents. To sum up, the two P. fluorescens isolates used in the present study might be usable for biocontrol of saprolegniosis and the mode of action of these bacteria is likely to be related to the production of siderophores (small compounds with high affinity binding for iron).Probiotics have been proposed as one of the alternatives to the chemical treatments currently used in aquaculture. Recently, the possible usefulness of certain microorganisms, mainly bacteria, has been highlighted as a potential biocontrol for saprolegniosis. In the present work we investigated the possible mechanisms of action of two isolates of Pseudomonas fluorescens (LE89 and LE141) with proven ability to reduce Saprolegnia parasitica infection in rainbow trout under experimental conditions when they are added to the tank water. The stimulation of the innate immune response and the production of siderophores and bioactive substances inhibiting S. parasitica present in cells and supernatants of LE89 and LE141 were studied. Regarding the immune response the only noteworthy points were the increase in the phagocytic activity of macrophages and the concentration of serum proteins when LE141 was administered. Both bacteria produced siderophores. When analyzing the protein substances present in supernatants, it was observed that in both isolates the proteins with inhibitory activity present might be siderophores. In LE141, besides siderophores, a protein of 66 kDa was identified in the fraction responsible for inhibition. To sum up, the two P. fluorescens isolates might be usable for biocontrol of saprolegniosis and that the mode of action of these bacteria is likely to be related to the production of siderophores.

Elucidating the pathogenic potential of Enterobacter cloacae SBP-8 using Caenorhabditis elegans as a model host

Enterobacter cloacae, an opportunistic nosocomial pathogen, is reported to possess different virulence factors that could potentially influence its pathogenesis. Generally, the E. cloacae infections are of endogenous origin occurring in immunocompromised patients. The mechanisms of pathogenicity remain elusive, possibly due to the absence of established model hosts. Thus, we explored the utility of Caenorhabditis elegans as a model host to test the pathogenicity of E. cloacae SBP-8, a soil isolate. E. cloacae SBP-8 progressively colonized the intestine of C. elegans. It induced cell death (as assessed through DNA damage), reproductive defect and reduction of lifespan, comparable to a clinical isolate, E. cloacae (MTCC 509). Observation with Nomarski microscopy revealed significant anterior pharyngeal distention, and altered egg arrangement with internal egg hatching in 70% infected worms. The internal egg hatching was observed as early as 48 h post infection. E. cloacae SBP-8 infection reduced the brood size by 16%. A 2′,7′-dichlorodihydrofluorescein diacetate staining confirmed the 10-fold induction of reactive oxygen species implicating either mitochondrial damage or septic shock in infected worms. Expression analysis through RT-PCR indicated stimulation of immune response by E. cloacae SBP-8 in worms by upregulating tol-1, a Toll-like receptor, within 6 h of exposure. During the initial phase of infection (up to 24 h) the nematodes exhibited protective immune response by upregulating antimicrobial peptide genes, lys-1, clec-60, clec-85, and clec-87. However, these genes were downregulated at later hours (48 h), indicating the nematodes surrendered to the infection. A similar trend was observed for reproductive genes (lin-29 and let-23), suggesting a struggle to maintain functional reproduction by the nematodes. These results clearly demonstrate the pathogenic potential of E. cloacae SBP-8 and suggest the suitability of C. elegans as a model organism to study its pathogenesis. This is the first study indicating that E. cloacae infections could potentially originate from an exogenic source (here soil).

Predictive Biomarkers of Response to Immunotherapy in Metastatic Renal Cell Cancer.

IntroductionIn the last decades, the therapeutic decision-making approach to metastatic renal cell cancer (mRCC) has dramatically changed thanks to the introduction in the treatment scenario of, first, anti-angiogenic agents and, afterward, immune-checkpoint inhibitors (ICIs). Immunotherapy is now the standard of care in pretreated mRCC patients and has recently entered even the first line setting. Nevertheless, in mRCC as well as in other tumor settings, a durable and clinically meaningful benefit from treatment with ICIs is not obtained for all patients treated. Therefore, the necessity to identify and validate predictive biomarkers of response to immunotherapy has emerged, in order to design the optimal treatment strategy for mRCC patients.DiscussionIn this review, we present and discuss the most promising predictive biomarkers of response to ICIs in mRCC with the recent data available. In details, the first marker that was investigated is the immunohistochemical expression of programmed death receptor ligand 1 (PD-L1), showing a negative prognostic role in mRCC, but the debate about its potential predictive value is still open. Additionally, the high heterogeneity in PD-L1 determination methods adds complexity to this issue. Second, the tumor mutational or neoantigen burden is an emerging biomarker of increased response to immunotherapy, hypothesizing that the higher the TMB, the higher is the production of neoantigens, and thus the stimulation of anti-tumor immune response, even though controversial results have been obtained. Third, the tumor microenvironment, namely the different populations of the immune infiltrate, plays a key role in tumor progression and in the response to immunotherapy. Finally, several studies have collected evidence on the potential association of the occurrence of immune-related adverse events (irAEs) with the benefit from ICIs, first in non-small cell lung cancer (NSCLC) and melanoma, and recently even in mRCC.ConclusionSeveral promising biomarkers of response to immunotherapy with ICIs have been identified, though without conclusive results upon their potential predictive value in mRCC. Therefore, the results of the exploratory analyses of the recently presented first-line trials and hopefully of future prospective, biomarker-driven studies could provide useful tools to be applied in the everyday clinical practice.

Combined hybrid structure of siRNA tailed IVT mRNA (ChriST mRNA) for enhancing DC maturation and subsequent anticancer T cell immunity

RNA therapeutics have received much attention in the development of anti-cancer therapies. Among them, synthetic mRNA (IVT mRNA) was investigated for cancer immunotherapy due to its abilities to express tumor associated antigens with stimulation of immune responses in dendritic cells (DCs). Despite of its great potential, several hurdles were remained such as insufficient immune stimulation and DC maturation. In this study, we aimed to present a novel IVT mRNA that can simultaneously express tumor associated antigens while suppress STAT3 proteins. Combined functions of siRNA and IVT mRNA were investigated and the hybrid structure of siRNA tailed mRNA (ChriST mRNA) was developed. We prepared the ChriST mRNA by employing polyA tail structures with RNAi sequences at the 3′ end of mRNA. Complementary strands were annealed to form duplex siRNA structure to induce STAT3 gene silencing. In addition, a hybrid structure of DNA/RNA was introduced into the ChriST mRNA between polyA tail and RNAi sequences. It was expected that DNA/RNA duplex would be readily cleaved by RNase H in the intracellular environment. After the cleavage, ChriST mRNA was fully functionalized in cells and exhibited enhanced tumor specific DC maturation.

A HSV1 mutant leads to an attenuated phenotype and induces immunity with a protective effect.

Herpes simplex virus type 1 (HSV1) is a complicated structural agent with a sophisticated transcription process and a high infection rate. A vaccine against HSV1 is urgently needed. As multiple viral-encoded proteins, including structural and nonstructural proteins, contribute to immune response stimulation, an attenuated or deficient HSV1 vaccine may be relatively reliable. Advances in genomic modification technologies provide reliable means of constructing various HSV vaccine candidates. Based on our previous work, an M6 mutant with mutations in the UL7, UL41, LAT, Us3, Us11 and Us12 genes was established. The mutant exhibited low proliferation in cells and an attenuated phenotype in an animal model. Furthermore, in mice and rhesus monkeys, the mutant can induce remarkable serum neutralizing antibody titers and T cell activation and protect against HSV1 challenge by impeding viral replication, dissemination and pathogenesis.

Application of the In Vitro HoxB8 Model System to Characterize the Contributions of Neutrophil-LPS Interaction to Periodontal Disease.

(1) Background: Studying neutrophils in vitro is difficult since these cells are terminally differentiated and are easily activated during isolation. At the same time, most of the available model cell lines are associated with certain limitations, such as functional deficiency or a lack of expression of surface markers characteristic of neutrophils. P. gingivalis is a periodontopathogen that causes dysbiosis in subgingival bacterial biofilm. This triggers the accumulation of functional neutrophils in the periodontium. However, until now, the specific effects of P. gingivalis-derived lipopolysaccharide on neutrophil functions have not been analyzed. (2) Methods: The impact of two variants of commercially available P. gingivalis endotoxin on neutrophil functions was tested using the HoxB8 in vitro system that is well suited to analyze neutrophil response to different stimuli in a controlled manner. (3) Results: The Standard P. gingivalis lipopolysaccharide (LPS), known to activate cells through Toll-like receptor 2 (TLR2)- and Toll-like receptor 4 (TLR4)-dependent pathways, prolonged neutrophil survival and exhibited pro-inflammatory effects. In contrast, Ultrapure LPS, binding exclusively to TLR4, neither protected neutrophils from apoptosis, nor induced an inflammatory response. (4) Conclusion: Two variants of P. gingivalis-derived LPS elicited effects on neutrophils and, based on the obtained results, we concluded that the engagement of both TLR2 and TLR4 is required for the manipulation of survival and the stimulation of immune responses of HoxB8 neutrophils.

Immunomodulating Efficacy Of Different Adjuvants In Formulation Of Foot And Mouth Disease Vaccine Relative To Its Immunogenicity

The ideal adjuvant is one that able to aid in early stimulation of the humeral immune response, and to promote the production of high antibody titers that would persist for long duration as well as stimulate the cellular immune response. This immunological study was conducted to reveal the aluminum hydroxide gel effect with the use of oil adjuvants on the immune response of polyvalent foot and mouth disease (FMD) vaccine in sheep. Twenty five sheep, were divided to five group (five animals/group) where the 1st group was vaccinated with polyvalent FMD ISA 206 oil vaccine, 2nd group was vaccinated with polyvalent FMD ISA 206 + aluminum hydroxide gel vaccine, 3rd group was vaccinated with polyvalent ISA 201 oil vaccine, 4th group was vaccinated with polyvalent ISA 201 + aluminum hydroxide gel vaccine, 5th group was kept as a negative control (non-vaccinated). Blood and Serum samples were collected from vaccinated animals for monitoring the cellular and humoral immune responses. The results showed that sheep groups immunized with the vaccine prepared with ISA 201with aluminum hydroxide gel is considered the best cellular and humeral immunity post vaccinal response then ISA 201 followed by ISA 206 with aluminum hydroxide gel and the last one is the vaccine prepared with ISA 206 alone.It can be concluded that ISA oils with aluminum hydroxide gel induce the best cellular and humeral immunity.

Targeting the NLRP3 Inflammasome in Severe COVID-19.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a member of the genus Betacoronavirus within the family Coronaviridae. It is an enveloped single-stranded positive-sense RNA virus. Since December of 2019, a global expansion of the infection has occurred with widespread dissemination of coronavirus disease 2019 (COVID-19). COVID-19 often manifests as only mild cold-like symptomatology, but severe disease with complications occurs in 15% of cases. Respiratory failure occurs in severe disease that can be accompanied by a systemic inflammatory reaction characterized by inflammatory cytokine release. In severe cases, fatality is caused by the rapid development of severe lung injury characteristic of acute respiratory distress syndrome (ARDS). Although ARDS is a complication of SARS-CoV-2 infection, it is not viral replication or infection that causes tissue injury; rather, it is the result of dysregulated hyperinflammation in response to viral infection. This pathology is characterized by intense, rapid stimulation of the innate immune response that triggers activation of the Nod-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome pathway and release of its products including the proinflammatory cytokines IL-6 and IL-1β. Here we review the literature that describes the pathogenesis of severe COVID-19 and NLRP3 activation and describe an important role in targeting this pathway for the treatment of severe COVID-19.

Reduced graphene oxide, but not carbon nanotubes, slows murine melanoma after thermal ablation using LED light in B16F10 lineage cells

Photodynamic therapy is a minimally invasive health technology used to treat cancer and other non-malignant diseases, as well as inactivation of viruses, bacteria and fungi. In this work, we sought to combine the phototherapy technique using low intensity LED (660 nm) to induce ablation in melanoma tumor in mice treated with nanoparticles. In vitro and in vivo studies were conducted, and our results demonstrated that multi-walled carbon nanotubes (MWCNTs) do not destroy tumor cells in vivo, but stimulate the inflammatory process and angiogenesis. Reduced graphene oxide (rGO), has been shown to play a protective role associated with the LED ablation, inducing necrosis, stimulation of immune response by lymphoproliferation, and decreased tumor mass in vivo. We consider that LED alone can be very effective in controlling the growth of melanoma tumors and its association with rGO is potentiated.

Photodynamic Therapy Enhanced Anticancer Efficacy of Cervical Cancer Through Immune Response Stimulation

Recent studies have identified photodynamic therapy (PDT) as a promising approach for cancer treatment. Here in this study, we have constructed hyaluronan (HA) coated metal-organic framework nanoparticles (MOF) as an artificial cell carrier (HA/MOF) to effectively delivery chlorin e6 (Ce6), a commonly adopted photodynamic reagent (HA/MOF/Ce6), to achieve enhanced PDT of cancer. In addition, apart from the generally recognized cytotoxicity induced by reactive oxygen species (ROS), our study also revealed that ROS could further potentiate the maturation of dendritic cells (DCs), which secreted tumor necrosis factor-α (TNF-α) and interleukin-12 (IL)-12 to trigger the following immune responses. Our work not only explore the anticancer feasibility of a new system but also demonstrated the underlining mechanisms responsible for PDT induced anticancer effects, which offers a new perspective to employ and improve the efficacy of PDT and related systems.

Advanced Foot-And-Mouth Disease Vaccine Platform for Stimulation of Simultaneous Cellular and Humoral Immune Responses.

Currently available commercial foot-and-mouth disease (FMD) vaccines have various limitations, such as the slow induction and short-term maintenance of antibody titers. Therefore, a novel FMD vaccine that can rapidly induce high neutralizing antibody titers to protect the host in early stages of an FMD virus infection, maintain high antibody titers for long periods after one vaccination dose, and confer full protection against clinical symptoms by simultaneously stimulating cellular and humoral immunity is needed. Here, we developed immunopotent FMD vaccine strains A-3A and A-HSP70, which elicit strong initial cellular immune response and induce humoral immune response, including long-lasting memory response. We purified the antigen (inactivated virus) derived from these immunopotent vaccine strains, and evaluated the immunogenicity and efficacy of the vaccines containing these antigens in mice and pigs. The immunopotent vaccine strains A-3A and A-HSP70 demonstrated superior immunogenicity compared with the A strain (backbone strain) in mice. The oil emulsion-free vaccine containing A-3A and A-HSP70 antigens effectively induced early, mid-term, and long-term immunity in mice and pigs by eliciting robust cellular and humoral immune responses through the activation of co-stimulatory molecules and the secretion of proinflammatory cytokines. We successfully derived an innovative FMD vaccine formulation to create more effective FMD vaccines.

Design of a Novel Multi Epitope-Based Vaccine for Pandemic Coronavirus Disease (COVID-19) by Vaccinomics and Probable Prevention Strategy against Avenging Zoonotics

The emergence and rapid expansion of the coronavirus disease (COVID-19) require the development of effective countermeasures especially a vaccine to provide active acquired immunity against the virus. This study presented a comprehensive vaccinomics approach applied to the complete protein data published so far in the National Center for Biotechnological Information (NCBI) coronavirus data hub. We identified non-structural protein 8 (Nsp8), 3C-like proteinase, and spike glycoprotein as potential targets for immune responses to COVID-19. Epitopes prediction illustrated both B-cell and T-cell epitopes associated with the mentioned proteins. The shared B and T-cell epitopes: DRDAAMQRK and QARSEDKRA of Nsp8, EDMLNPNYEDL and EFTPFDVVR of 3C-like proteinase, and VNNSYECDIPI of the spike glycoprotein are regions of high potential interest and have a high likelihood of being recognized by the human immune system. The vaccine construct of the epitopes shows stimulation of robust primary immune responses and high level of interferon gamma. Also, the construct has the best conformation with respect to the tested innate immune receptors involving vigorous molecular mechanics and solvation energy. Designing of vaccination strategies that target immune response focusing on these conserved epitopes could generate immunity that not only provide cross protection across Betacoronaviruses but additionally resistant to virus evolution.

Selection of putative probiotics based on antigen-antibody cross-reaction with Photobacterium damselae subsp. piscicida and Vibrio harveyi for use in Senegalese sole (Solea senegalensis)

Probiotics can be used to reduce disease outbreaks in aquaculture. Some of them are characterised by their antagonistic activity against pathogens or the stimulation of the fish immune response, including the production of specific antibodies. If a probiotic has common antigens with a determined pathogen, it could produce antibodies with a cross-reaction to that pathogen. Thus, a probiotic with these characteristics could be used in a similar way to a live vaccine. The aim of this study was to select bacteria with antigenic similarity and antagonistic activity against the pathogens Photobacterium damselae subsp. piscicida and Vibrio harveyi, and to determine their ability to stimulate the production of antibodies in sole (Solea senegalensis, Kaup) with cross-reaction against these pathogens.Dot blot was used to detect strains with cross-reaction using sera immunized against P. damselae subsp. piscicida Lg41.01 and V. harveyi Lg16.00. A total of 138 strains were selected from 718 strains, based on the intensity of the dot blot reaction. A second selection was performed to detect their ability to inhibit the pathogens growth. Five strains inhibited the growth of P. damselae subsp. piscicida, four strains inhibited the growth of V. harveyi, while two strains inhibited both pathogens. A Western blot confirmed the cross-reactions of the selected strains with the pathogens.Selected strains were subsequently inoculated into sole specimens by intraperitoneal injection. Four strains produced antibodies with cross-reaction against the pathogens. None mortality was observed in the inoculated fish. Further research demonstrated the storage capability of the selected strains in saline solution and feed, their growth at low pH, and identified their enzymatic characteristics. In conclusion, the selected strains showed antimicrobial activity and capacity to activate a specific immune response against fish pathogens.

Immunoinformatic analysis of the SARS-CoV-2 envelope protein as a strategy to assess cross-protection against COVID-19

Envelope protein of coronaviruses is a structural protein existing in both monomeric and homo-pentameric form. It has been related to a multitude of roles including virus infection, replication, dissemination and immune response stimulation. In the present study, we employed an immunoinformatic approach to investigate the major immunogenic domains of the SARS-CoV-2 envelope protein and map them among the homologue proteins of coronaviruses with tropism for animal species that are closely inter-related with the human beings population all over the world. Also, when not available, we predicted the envelope protein structural folding and mapped SARS-CoV-2 epitopes. Envelope sequences alignment provides evidence of high sequence homology for some of the investigated virus specimens; while the structural mapping of epitopes resulted in the interesting maintenance of the structural folding and epitope sequence localization also in the envelope proteins scoring a lower alignment score. In line with the One-Health approach, our evidences provide a molecular structural rationale for a potential role of taxonomically related coronaviruses in conferring protection from SARS-CoV-2 infection and identifying potential candidates for the development of diagnostic tools and prophylactic-oriented strategies.

Endogenous TLR2 ligand embedded in the catalytic region of human cysteinyl-tRNA synthetase 1

BackgroundThe generation of antigen-specific cytotoxic T lymphocyte (CTL) responses is required for successful cancer vaccine therapy. In this regard, ligands of Toll-like receptors (TLRs) have been suggested to activate adaptive...